1. Field of the Invention
The present invention relates generally to gas safety valves and, more specifically, to the gas safety valves which are used for the supervised control or shutoff of the gas supply in case of a leak, an emergency, or an administrative procedure. This invention also relates to the field of gas meters and the remote operation of the gas supply.
2. Discussion of the Background
At present, gas meters can be classified into several categories: (a) displacement, such as rotary, diaphragm, and turbine, (b) fluidic, such as vortex-shedding meters, and (c) thermodynamic, such as ultrasonic time of flight meters and thermal loss meters. The displacement meters of the rotary type, where intermediate flows are encountered, have been in use in commercial and industrial settings for many years. Such gas meters and their improvements are discussed in the following patents, which are incorporated herein by reference:                A. U.S. Pat. No. 5,637,805 to Adams, et al. ('805);        B. U.S. Pat. No. 5,046,369 to Boyd, et al. ('369);        C. U.S. Pat. No. 4,918,995 to Pearman, et al.; and        D. U.S. Pat. No. 4,910,519 to Duell, et al. ('519).        
The procedure for reading residential, commercial, or industrial gas meters is a laborious and costly process. It is therefore very desirable to have a method through which the gas meter can be remotely read for billing purposes. There have been several inventions that apply to this matter, but all of these typically require an external supply or battery power for proper operation.
For instance, U.S. Patent '369 discloses a flow meter capable of operating from a variety of sources, such as the AC supply mains, or solar panels feeding storage batteries. The first source is costly in a remote location, and may introduce some hazards in the implementation. The second source is cumbersome, costly, and subject to vandalism in urban settings. In addition, U.S. Patent '805 discloses the use of a battery pack of D cells, which are very costly to maintain or replace periodically.
Emergencies or administrative procedures, both requiring that the gas supply be shutoff, may arise in the premises or general location where the gas meter is located. Currently, there are several proposed solutions to shutting off the gas supply remotely. For example, U.S. Pat. No. 5,209,454 to Engdahl et al. ('454) discloses a safety shutoff valve for insertion into a gas line or other fluid line, which closes in response to an electrical input pulse or to a seismic disturbance. However, even though the invention of '454 allows for the closing of the shutoff valve from a remote location, it teaches a manual reset.
In addition to the foregoing, U.S. Pat. No. 5,484,103 to Schultz ('103) and '454 both disclose solenoid actuated valves which require energy expenditures at higher voltages and currents, which limits their usefulness in an ambient of explosive mixtures or at a location with limited access to power mains. The installation of an external power connection can be very expensive and may require special arrangements with the power company. In addition, external energy supplies have to be installed within special enclosures to minimize the danger of an explosion in a hazardous environment.
The following patents are pertinent to this topic and are incorporated herein by reference:                A. U.S. Pat. No. 5,575,309 to Connell which discloses a solenoid actuator for a fluid flow valve.        B. '995 which discloses an electronic compact gas meter including a solid state flow sensor for sensing gas flow rate, data acquisition circuits including an analog-to-digital converter coupled to the sensor for controlling the same and providing an output indicative of gas flow, and a digital data processor for receiving the gas flow information from the analog-to-digital converter, processing the information and registering the volumetric gas flow reading at the meter and/or transmitting the volume flow information via wireless or telephone communication lines to a remote location;        C. '519 which discloses electronic volume correctors which sample the mechanical metered volume reading of the flow through a gas pipeline according to the gas laws, which incorporate the pressure and temperature parameters of the gas, with analog sensors and inputs them into an analog to digital converter. The digital output from the converter is employed to obtain a more accurate digital volume reading.        D. U.S. Pat. No. 5,595,207 to Jiles which discloses a tension actuated gas shutoff valve having a body with an inlet for receiving gas flow along a flow path from upstream to downstream and a piston slidable within the body. The piston slides in response to a longitudinal force applied across the valve between a first position wherein flow through the valve is prevented and a second position wherein flow through the valve is permitted.        E. U.S. Pat. No. 5,584,465 to Ochsenreiter which discloses a solenoid latching valve movable between open and closed positions employing a latching magnet and a spring to maintain a plunger in the open and closed positions respectively.        F. U.S. Pat. No. 4,921,008 to Foster which discloses an automatic emergency fluid flow shutoff device for use primarily with gas cylinder operations wherein a ball located in the device completely closes off an orifice to stop further gas flow when there is a sudden loss of resistance downstream of the device due to a cut hose or a fire from a severed hose. The device also incorporates a gas flow meter or pressure gauge as part of the reset mechanism thus eliminating additional connectors.        
Various gas safety valves have recently been disclosed, yet none provide a remotely operable, cost efficient, gas safety valve such as the gas safety valve of the present invention.
While these devices or methods in the prior art fulfill their respective, particular objectives and requirements, none of them, however, provide a remotely operated self-powered gas safety valve that takes advantage of the technology developed to date in order to remotely, securely, and automatically shutoff and reset the gas supply in case of an emergency. Thus, it can be appreciated that there is a continuing need for a new and improved remotely operated self-powered gas safety valve which overcomes these and other deficiencies in the prior art. In this regard, the present invention substantially fulfills this need.
However, none of the existing art, taken either simply or in combination teach the use of the very principle of the meter to derive the necessary electric energy to power the electronic circuits and devices required to remotely read a gas meter and control a valve. Additionally, none of the existing art teaches the use of an energy storage management system for the controlled charging and use in an intrinsically safe manner. In this respect, the device according to the present invention substantially departs from the conventional concepts and designs of the prior art to fulfill the aforementioned need.